conserved catalytic core domain of RNA-dependent RNA polymerase (RdRp) from the positive-sense single-stranded RNA [(+)ssRNA] viruses and closely related viruses; This family contains the catalytic core domain of RdRp of RNA viruses which belong to Group IV of the Baltimore classification system, and are a group of related viruses that have positive-sense (+), single-stranded (ss) genomes made of ribonucleic acid (RNA). RdRp (also known as RNA replicase) catalyzes the replication of RNA from an RNA template; specifically, it catalyzes the synthesis of the RNA strand complementary to a given RNA template. The Baltimore Classification is divided into 7 classes, 3 of which include RNA viruses: Group IV (+) RNA viruses, Group III double-stranded (ds) RNA viruses, and Group V negative-sense (-) RNA viruses. Baltimore groups of viruses differ with respect to the nature of their genome (i.e., the nucleic acid form that is packaged into virions) and correspond to distinct strategies of genome replication and expression. (+) viral RNA is similar to mRNA and thus can be immediately translated by the host cell. (+)ssRNA viruses can also produce (+) copies of the genome from (-) strands of an intermediate dsRNA genome. This acts as both a transcription and a replication process since the replicated RNA is also mRNA. RdRps belong to the expansive class of polymerases containing so-called palm catalytic domains along with the accessory fingers and thumb domains. All RdRps also have six conserved structural motifs (A-F), located in its majority in the palm subdomain (A-E motifs) and the F motif is located on the finger subdomain. All these motifs have been shown to be implicated in RdRp fidelity such as processes of correct incorporation and reorganization of nucleotides. In addition to Group IV viruses, this model also includes Picobirnaviruses (PBVs), members of the family Picobirnaviridae of dsRNA viruses (Baltimore classification Group III), which are bi-segmented dsRNA viruses. The phylogenetic tree of the RdRps of RNA viruses (realm Riboviria) showed that picobirnaviruses are embedded in the branch of diverse (+)RNA viruses; sometimes they are collectively referred to as the picornavirus supergroup. RdRps of members of the family Permutatetraviridae, a distinct group of RNA viruses that encompass a circular permutation within the RdRp palm domain, are not included in this model.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1774088445   1 ATFCPAKLRSYPKKHEYRAPNIRSAVPSAMQNTLQNVLIAATKRNCNVTQMRELPTLDSATFNVECFRKYACNDEYWEEF 80
Cdd:cd23250    12 ATFCPAKLRSYPKKHAYHQPQIRSAVPSPFQNTLQNVLAAATKRNCNVTQMRELPTLDSAAFNVECFKKFACNNEYWEEF 91

                          90       100       110
                  ....*....|....*....|....*....|....*.
gi 1774088445  81 ARKPIRITTEFVTAYVARLKGPKAAALFAKTHNLVP 116
Cdd:cd23250    92 KEKPIRLTTENVTTYVTKLKGPKAAALFAKTHNLVP 127

RNA-dependent RNA polymerase (RdRp) in the family Togaviridae of positive-sense single-stranded RNA [(+)ssRNA] viruses; This group contains the RdRp of RNA viruses belonging to the family Togaviridae, order Martellivirales. Togaviridae is a family of small, enveloped viruses with [(+)ssRNA] genomes of 10-12 kb, and contains a single genus, Alphavirus. Alphavirus includes a large number of species that are mostly mosquito-borne and pathogenic in their vertebrate hosts. Many are important human and veterinary pathogens (e.g., chikungunya virus, eastern equine encephalitis virus). The genus Alphavirus mainly consists of mosquito-borne viruses although other hematophagous insects, including ticks, lice, and cliff swallow bugs, have been implicated in transmission. Vertebrate hosts include humans, non-human primates, equids, birds, amphibians, reptiles, rodents, and pigs. There are two aquatic alphaviruses, southern elephant seal virus and salmon pancreas disease virus, infecting sea mammals and fish respectively. Interestingly, Eilat virus (EILV) has been shown to only infect insect cells and is incapable of replicating in vertebrate cells. The RdRp domain displays a right hand with three functional subdomains, called fingers, palm, and thumb. All RdRps contain conserved polymerase motifs (A-G), located in the palm (A-E motifs) and finger (F-G) subdomains. All these motifs have been implicated in RdRp fidelity such as processes of correct incorporation and reorganization of nucleotides.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1774088445   1 ATFCPAKLRSYPKKHEYRAPNIRSAVPSAMQNTLQNVLIAATKRNCNVTQMRELPTLDSATFNVECFRKYACNDEYWEEF 80
Cdd:cd23250    12 ATFCPAKLRSYPKKHAYHQPQIRSAVPSPFQNTLQNVLAAATKRNCNVTQMRELPTLDSAAFNVECFKKFACNNEYWEEF 91

                          90       100       110
                  ....*....|....*....|....*....|....*.
gi 1774088445  81 ARKPIRITTEFVTAYVARLKGPKAAALFAKTHNLVP 116
Cdd:cd23250    92 KEKPIRLTTENVTTYVTKLKGPKAAALFAKTHNLVP 127

RNA-dependent RNA polymerase (RdRp) in the family Togaviridae of positive-sense single-stranded RNA [(+)ssRNA] viruses; This group contains the RdRp of RNA viruses belonging to the family Togaviridae, order Martellivirales. Togaviridae is a family of small, enveloped viruses with [(+)ssRNA] genomes of 10-12 kb, and contains a single genus, Alphavirus. Alphavirus includes a large number of species that are mostly mosquito-borne and pathogenic in their vertebrate hosts. Many are important human and veterinary pathogens (e.g., chikungunya virus, eastern equine encephalitis virus). The genus Alphavirus mainly consists of mosquito-borne viruses although other hematophagous insects, including ticks, lice, and cliff swallow bugs, have been implicated in transmission. Vertebrate hosts include humans, non-human primates, equids, birds, amphibians, reptiles, rodents, and pigs. There are two aquatic alphaviruses, southern elephant seal virus and salmon pancreas disease virus, infecting sea mammals and fish respectively. Interestingly, Eilat virus (EILV) has been shown to only infect insect cells and is incapable of replicating in vertebrate cells. The RdRp domain displays a right hand with three functional subdomains, called fingers, palm, and thumb. All RdRps contain conserved polymerase motifs (A-G), located in the palm (A-E motifs) and finger (F-G) subdomains. All these motifs have been implicated in RdRp fidelity such as processes of correct incorporation and reorganization of nucleotides.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1774088445   1 ATFCPAKLRSYPKKHEYRAPNIRSAVPSAMQNTLQNVLIAATKRNCNVTQMRELPTLDSATFNVECFRKYACNDEYWEEF 80
Cdd:cd23250    12 ATFCPAKLRSYPKKHAYHQPQIRSAVPSPFQNTLQNVLAAATKRNCNVTQMRELPTLDSAAFNVECFKKFACNNEYWEEF 91

                          90       100       110
                  ....*....|....*....|....*....|....*.
gi 1774088445  81 ARKPIRITTEFVTAYVARLKGPKAAALFAKTHNLVP 116
Cdd:cd23250    92 KEKPIRLTTENVTTYVTKLKGPKAAALFAKTHNLVP 127